Synthesis of enones
Starting from readily available aryl iodides and allenes, with formic acid as the CO source and reductant, good yields of α-branched enones were isolated. The use of a CO source avoids the manipulation of CO gas.
H.-Q. Geng, L.-C. Wang, C.-Y. Hou, X.-F. Wu, Org. Lett., 2020, 22, 1160-1163.
A carbonylative Suzuki-Miyaura coupling reaction of lactam-derived vinyl triflates and alkenylboronic acids afforded 2-(N-methoxycarbonylamino)-1,4-pentadien-3-ones in good yield.
P. Larini, A. Guarna, E. G. Occhiato, Org. Lett., 2006, 8, 781-784.
A highly efficient catalytic, intermolecular synthesis of the cyclopentane skeleton from simple starting products is reported. Allyl halides, alkynes, and carbon monoxide react under very mild reaction conditions by means of a substoichiometric amount of iron, acetone, and a catalytic amount of Ni(II) iodide.
M. L. Nadal, J. Bosch, J. M. Vila, G. Klein, S. Ricart, J. M. Moretó, J. Am. Chem. Soc., 2005, 127, 10476-10477.
A new approach to 2-(arylmethyl)aldehydes begins with a silylformylation reaction of terminal acetylenes with aryl- or heteroarylsilanes, followed by treatment of the products with TBAF to induce a 1,2-anionotropic rearrangement of the aryl group.
L. A. Aronica, P. Raffa, A. M. Caporusso, P. Salvadori, J. Org. Chem., 2003, 5, 9292-9298.
An entrapped Rh catalyst derived by a sol-gel process has been used in a Pauson-Khand reaction under mild conditions. The catalyst can be reused at least 10 times without losing activity. This catalytic system is not effective for intermolecular reactions.
K. H. Park, S. U. Song, Y. K. Chung, Tetrahedron Lett., 2003, 44, 2827-2830.
Indanones and 2-cyclopentenones have been successfully prepared in good to excellent yields by the palladium-catalyzed carbonylative cyclization of unsaturated aryl iodides and dienyl triflates, iodides, and bromides, respectively. The mechanism is discussed.
S. V. Gagnier, R. C. Larock, J. Am. Chem. Soc., 2003, 125, 4804-4807.